Flame hardening of internal cylindrical surfaces



Sept. 27, 1949.

Filed Aug. 21. 1946 R. M. ROOKE FLAME HARDENING OF INTERNAL CYLINDRIGAL SURFACES 2 Sheets-Sheet l a .0 duh ROBERT M. ROO/(f ATTORNEY Sept.27, 1949. I R. M. ROOKE FLAME HARDENING-OF INTERNAL CYLIND RICAL SURFACES Filed Aug. 21, 1946 2 Sheets-Sheet 2 l 'TFf" v I v INVENTOR ROBERT IV: ROOAE BY Ed 6M MC 0 ATTORNEY Patented Sept. 2?, 1949 a.

um'rso asr rr-:s PATENT OFFICE HARDENING or INTERNAL ,,'CYLINDRICAL SURFACES Robert M. Rooke, Long Branch, N. J., assignor to Air Reductionicompany, Incorporated, New 7 York,;- N. Y.,, a corporation of New York ff Application August '21, 1946, Serial No. 692,057

This invention relates to' the hardening of cylindrical surfaces of 'cast iron, steel and the like, and particularly'to an improved method of and apparatus for effecting such hardening.

It has been suggested heretofore that internal cylindrical surfaces of iron, steel and the like'can be hardened'by subjecting the surface to heating by a circumferential row of radially disposed flames and thereafter quenching the heated surface. With the workpiec'e in vertical position, the quenching water drains away as rapidly as it is applied. Consequently heat in the underlying metal is conducted'to the hardened surface and tends toanneal and thus eliminate the hardening effect for whi'ch the procedure is designed.

It is the object of the present invention to provide a method of and apparatus forhardening internal cylindrical surfaces by heating and quenching, including improvements which facilitate the operation and ensure successful production of hardening of uniform depth over the surface treated. 1 h Y Another object of the'invention is the maintenance of a -pool Of quenching liquid in contact with the surface 'metal so that heat in the underlying metal is removed and annealing of the hardened surfaceis prevented. I

Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specification and the accompanying drawing, in which Fig. 1 is a sectional view showing a suitable heating device for the practice of the invention disposed in a cylindrical body, such as apump liner, in operative positionto' permitapplication of the method for hardening the surface;

Fig. 2 is a fragmentary sectional view taken on the line 2-2 of Fig. 1; r

Fig. 3 is an elevation of a driving mechanism adapted to permit manipulation of the device to secure the desired result. 7

In accordance with the i'nventiorna cylindrical surface is subjected to heating around a relatively narrow circumferential substantially horizontal portion, to a temperature'above the-critical range for the metal treated, and immediately thereafter the heated portion is quenched. The procedure is carried out progressively as the heating flames, arranged in a circumferential band, are moved upwardly at a substantially'um'form rate from the bottom to the topof the cylindrical surface, with the quench following progressively behind'the band offiames.

The heating is efiected by fiames' produced by anycombustible and oxidizing gas supplied there- 6 Claims. (01. 148 -2156)- to in a mixture of proper proportions. Oxyacetylene flames are well adapted for the 'purpose of the invention, but other gases may be used so long as the flames are capable of heating the metal rapidly to the desired temperature.

In order to hold a substantial pool of quenching liquid in. contact with the cylindrical surface long enough to remove heat from the metal behind the quenched surface, a baflie is provided beneath the flames. The quenching liquid such a as water which is delivered from the quenching jets is in sufficient volume to accumulate above the baffie. The latter is arranged to permit overflow of any excess of liquid.

In the/practice of the method, it is desirable also to maintain the surface of the metal above the heating zone at a relatively low temperature and to prevent the uneven'preheating that is caused by conduction of heat through the metal ahead of the flames and by contact of the surface metal with combustion gases rising from the flames. This result, as well as control of combustion v of the envelope gases, is effected by supplying a blast of cold gas such as air through a plurality of circumferentiallydisposed orifices above the heating zone. The cold gas impinges on the surface metal, removes heat conducted through the metal, and dilutes and reduces the temperature of the combustion gases. Thus uneven heating of the surface at different regions along its length is prevented, and it is possible to advance the heating flames at a uniform rate instead of progressively increasing the speed of the heating-device as is otherwise necessary in order to prevent overheating'of the upper portions of the surface treated. I

To facilitate the operation, it is also desirable to support the workpiece in such a Way as to ensure eifectiveness of the liquid seal before starting the initial heating at the lower end of the surface to be treated. For that purpose, the workpiece is mounted upon a fixture having an opening conforming in diameter substantially to the diameter of the cylindrical opening in the workpiece. The heating device which is moved upwardly from the lower end of the fixture establishes the water seal therein before the flames engage and heat the lowermost portion of the. surface tobe treated.

Referring to Fig. 1 of the drawing, 2 indicates a. fixture having a bore 3 and a ledge 4 which is adapted to support the workpiece 5 consisting of a cylindrical body having a bore or cylindrical surface {which is adapted" to-be hardened by the a practice of the invention as described herein. A

tubular member ID. A threaded ;nipple I6, also secured to the block I3, is adapted to" be con nected by a hose (not shown) to a source of acetylene which flows through a passage II to a groove I8 and thence through inlets I9 into the mixing chamber l where it mixes with'the oxygen and provides the fuel to maintain the heating jets. A tubular member surrounds the member Ill. One end of the member 20 sets on a ledge in the block 9 and the other end is conical and seats against the conicalseat I2 of the block I3. The member 20 is secured to the block l3 by a nut 20a which holds the conical end firmly against the seat I2. A nut 2| surrounds the member 20 and threads into the block 9, packing 22 being disposed behind the nut 2| to prevent the leakage of gaS from the annular passage 23 formed between the member Ill and the outer member 21!. This passage 23 communicates through a passage 24 in the block I3 (Fig. 2) with a nipple 25 which is adapted to beconnected through a hose (not shown) with a source of quenching medium such as water.

Within the tubular member 8 are two concentric tubes 25 and 21 forming passages 28, Hand 30. The lower end of the tube 21 terminates in a threaded nipple 3| which is adapted to be connected through a hose (shown dotted) with a source of air or other coolin gas under pressure. The latter is conducted through thetube 21 to a chamber 32 at the top of the torch head I, and a plurality of orifices 33 distribute the cooling gas circumferentially about the torch head in a plurality of jets which impinge upon the cylindrical surface 6.

Directly beneath the chamber--32 is achamber 34 which communicates with the passage 29 between the tubes 26 and '21. This passage in turn communicates with the mixing chamber l5 and. thus the mixture of, combustible and oxidizing gas is delivered to the chamber 34 and distributed through a set of staggered orifices 35 disposed circumferentially about the torch head I. When ignited. the gaseous mixture formsa, plurality of flame jets which impinge upon the cylindrical surface 6 to effect thedesired heating thereof.

Below the chamber 34 is a third chamber 36 communicating with the passage 28 formed between the tubular member 8 and the concentric tube 26, and this passage 28 communicates, through a passage 31 and a passage 38, with the passage 23 in the tubular member 2|]. This affords a supply of quenching medium, such as water, to the chamber 36. The water is distributed through a plurality of circumferentially disposed orifices 33' in the torch head I 'so that the quenching medium impinges upon the surface 6 below the flame jets.

A bafile ll is supported beneath the torch head I. Having a diameter only very slightly less than that of the bore 6, it is adapted to hold a substantial volume of the quenching water trapped against the side of the bore just belowthe quenching jets. This pool of Water is agitated by the water running downfrom the quenchin jets 4 and serves as an effective and substantially uniform cooling medium for preventing the reheating of the surface metal by heat conducted back to the surface from the underlying metal. This water maintains an effective seal against the upward passage of air as the result of draft created by the heated combustion gases. In order that the proper volumeof liquid may be maintained, the baffle 4| is provided with a number of tantalus tubes 42 through which the surplus water is drained whenever the level rises to a predetermined maximum. As will be apparent, the water seal becomes effective within the bore of the fixture 2 before the heating flames impinge upon the surface 6.

Thereafter the quenching effect is uniform throughout the length of the workpiece and no air can rise through the space defined by the surface 6.

To effect the vertical movement of the torch head I, the block 9 may be mounted in any suitable clamping device such as clamps .55 which are rigidly attached to a support 56 fixed to a base 51. This'base 51 is supported by a piston rod 58 of a hydraulic motor 59 (Fig; 3). A fixed guide 60 maintains the torch head centeredin the workpiece. However, any other device capable of moving the torch vertically may be employed. Thus, with the torch head I disposed below the lower edge of the surface 6, the combustible gas may be ignited to produce the flame jets. The quenching water may be turned on, and when the baffle 4| is in the fixture 2, the water provides the seal. Thereafter the torch head maybe raised at a uniform speed into and through the cylindrical workpiece to be hardened. As thetorch head I rises, each increment of the surface 6 is subjected successively to the cooling effect of the cooling gas, is then heated rapidly to the critical temperature, and quickly thereafter is cooled by the cooling medium to reduce the temperature and efiect the desired hardening of the surface. The mass of water trapped above the baflle 4| ensures uniform quenchin results.

The surface 6 above the level of the heating flames is continuously maintained at low temperature as the result of the large volume of cooling medium which continuously impinges on and flows upwardly over the surface. The desired hardening effect of uniform character, is thus effected.

A deflecting shield BI is removably attached to the fixture 2 by supporting links 62 and rotatable dogs 63. The quench water falls on this deflecting shield BI and is directed by a lip 64 to run off at the desired point.

Various changes may be made in the details of the operation and in the apparatus employed without departing from the invention or sacrificing the advantages thereof.

I claim: 7

1. The method of hardening internal cylindrical surfaces of metal bodies which'comprises directing a plurality of radially disposed heating flames against a substantially horizontal circumferential portion of the surface, moving the flames vertically and upwardly along the surface, quenching the heated surface immediately after the heating flames have been removed therefrom and maintaining a pool of quenching liquid in contact with the internal cylindrical surface and below the heating flames. I 7

2. The method of hardening internal cylindrical surfaces of metal bodies which comprises directing a plurality of radiallydisposed heating flames against a substantially horizontal circumferential portion of the surface, moving the flames vertically and upwardly along the surface, cooling the surface above the heating flames to a relatively low temperature, quenching the heated surface immediately after the heating flames have.

been removed therefrom a'ndmaintaining a pool 6 contact with the internal cylindrical surface, and overflow means for the quenching liquid forming the pool above said flange positioned above the 'level of the lower portion of the flange to maintain-quenching liquid in the pool at a substantially uniform predetermined level.

of quenching liquid in contact with the internal cylindrical surface and below the heating flames.

3. The method'of hardening internal cylindrical surfaces of metal bodies as set forth in claim 1 in which the pool of quenching liquid is maintained at a substantially uniform .predetermined depth.

4. An apparatus for hardening internal cylin--v drical surfaces of metal bodies While they are supported in a vertical position comprising a torch support, a torch head carried by said support having a plurality of circumferential rows of orifices, means for supplying a mixture of combustible and oxidizing gases to one of said rows of orifices,

means for supplyingaquenching liquid to a row a of said orifices which is below the row of orifices to which the combustible and oxidizing gases is supplied when the torch is inoperative position within the cylindrical surface, an annular flange extending from the torch support beneath the torch head when the latter is in operative position within the cylindrical surface, the outer diameter of the flange being only slightly less than the internal diameter of the cylindrical surface so that the peripheral edge of the flange lies closely adjacent the cylindrical surface when therein and cooperates with said surface to maintain a pool of quenching liquid below the torch head and in 5. An apparatus for hardening internal cylindrical surfaces of metal'bodies as defined in claim 4 in which the overflow means includes tantalus tubes. v

6. An apparatus for hardening internal cylindrical surfaces of metal bodies as defined in claim iwhich includes means for supplying a blast of cold gas to a row of the orifices which is above the row of orifices to which the combustible and oxidizing gases is supplied when the torch is in operative position within the cylindrical surface.

ROBERT M. ROOKE'.

REFERENC ES CITED ,The following references are of record in the file of this patent:

V 3 UNITED STATES PATENTS 

